Microcystin-producing cyanobacteria are common nuisance organisms in harmful algal blooms in freshwaters around the world. This ground breaking work lead by the Department of Microbiology, University of Tennessee provides a detailed analysis of the genetic diversity within microcystin producing cyanobacteria. Molecular tools offer an advantage over more traditional chemical measures of toxin concentration, as they may serve as a predictor of potential bloom events to come (while toxin measurements suggest that the event, and potential exposures, have already occurred).